SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '983a2f5e9f4679af33a4595bcc77976a38e12a320b99a35efd397cae32b6f358' 
  AND token = 'i0Savmw66QMAUK4dRkazRF6FPEOeyzAkiF8CukcXQ9g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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