SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46a2bc1c6926381cc4aa1407eca1f76586f484260380a8eb90e3b3f4e357258b' 
  AND token = 'Zh36NBgawfCz+hkhkjvJI6L5nkAKVjo6Z1ujKWrmkKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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