SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30980d17bd17809f4cb3872a774626b64072ced689876157d172a0320a5652c0' 
  AND token = 'gX9pgqvzXjagzr0Xf1TrtOGwjrzmuZ8KHPFBC+3vd3Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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