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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c51d1af1a702324cc187917b36582d2bd6ea3a1abb6e603506f23ea87e7b7ee4' 
  AND token = 'zcG8uSIF5beyM2UU+IWc9qfdQV5xMNTMqSkydt6A8IE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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