SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4a0a0c9882683c1aefddd221623c5786b3bbbca1b2cba72668d1766b17517d0' 
  AND token = 'pCkROzweLolhrdBWWBwIXANjVaWxv912zs2qkvvObMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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