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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6a8b3b5cf9852347c42bad85ecb8a7aea4d4e3c71f51c3a7cc5f2fbfc7dc14e' 
  AND token = 'qj6WbrYq7LMv0eqqRichA8Yl3qBM2Oh+rHhTOge12wo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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