SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '791e3685eef4aec618a7f31978c7d1765999c57dfdd608f74f749dbd2167f184' 
  AND token = 'BcE9pt54jiOzAAv4iGCg5hUGg6TyqX7b6hFT/CAMrMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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