SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '203a5ae22bf3f4eb58308758cca642432dcd33af75e1827a4db61c6b33298455' 
  AND token = '5gjO2vRezBMNWkJq3KWeBlbkMsLYm6QqA/yQciRK3u8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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