SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '498f5607b8b5dde36d919117addc3622f721e0dea79528683dddf7afc0ac1143' 
  AND token = '5Nz9/KmA30hpPK972+DmXyGOZBUSsUHtCpZJCTgEJ68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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