SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c207cf4baa9a1978608cf09f787eba823817e5ffe5a05dde46a97a28c225477' 
  AND token = '34OMR2+icuQJObzm80WnmcMebvMeVWWMqbtglY7gKxA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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