SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a28b8bc939bb72a81a929d9b19d2c203080787044e1fa90f161884ea8a0f753d' 
  AND token = 'DT+ShTaFYk5knQ7kM50LBFwfGACpgNVkfrV5GZ+iACs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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