SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '430c21968162b6fe673b5a7b2ec7d89368205b1d417df22919524add2e9fbe20' 
  AND token = 'tjFtfaxAINqOXYhQ0nsmR+G4xJ0bsvHKoX1fpVHA5p4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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