SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b36205656781c2a85d332a76d5deb4dd681607f9249cb7834d2ecba0b1d1c19e' 
  AND token = 'kSQEzdTA6SAJcG4vnZ1HX7RIdXV5OJ6NK6nZAw3/uYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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