SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdb29515eb0fc63537b021d29c983f3598abe5e0de928e6f6f8f75a393845736' 
  AND token = 'C9Wa7CtkaBDRqP/qWYR3tZwG5YCLcCivteDaKnX8P6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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