SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd471ce40c23e2d7b1892a4271b61f0f2bbb1155449f5313aafdf4b931a1a8474' 
  AND token = 'IoPNfbKa5TvTQH7ifIIGZlJeK/nkHxcK+vjjPYA3UCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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