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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f9290d76b5f3fc9f77c676e8a9068d56f296d226655e4b9be9c80461af13a19' 
  AND token = 'xPhZuc4CsahkkVv1PvNdKM5btR+SUReChmPZRyLuPD4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}