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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a50f4c64404591cc4a7ec0c39244c479106e1ce7e8fb7a126af986e0ce1ab17f' 
  AND token = 'De5Bqo2ZOr1jBe+drXcc4L9+xCmPCbRiB+tUbvxQC9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}