SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0eb4118abf9ffa252a971dca1816f05c9cb3cb8dc70bf5b517b856de8d5a1080' 
  AND token = '+UgrbdS0o9N3yJCcRIpsPRjh68EJPa8R6thLKZ7Q9m0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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