SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5469c4580f12be30b26540474050df0602beef64d7029fb302890dc6225b7051' 
  AND token = 'lx6E9+orqvQrS3vvYA4PmXuVMdKPWiP2zM1oY6coBwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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