SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa8ce0027494bc365770b11e6fd5b09121495f2fb6d989c70b88be6167671f73' 
  AND token = 'H7rlUf5nVdRlCcWYXiWLboFmEnSgLJGa2ksgn1elIgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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