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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fa6fd3ee1e021e9c5cd16346c4347733263ce86a99a89488f7a6b946a6e4a742' 
  AND token = 'wlnCXWmkj5MyrZTPLirQRHoXs1+LmG6FvYLzAQMnDIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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