SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'cd6d72b67a0de1c38f9572e42b8f744be142b884f97d6c0c8c97954280584b2d' 
  AND token = 'g1z6kMBMnPFOzlZ4Usq27jhbDIe0ZwW5VN2JSjkf7+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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