SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4f8a6b206551ce89655c255fb8b4e4db812b4ea75d5deb8bed2ff20c49e4786' 
  AND token = 'xbTrEbEVn9FaDi6d+/B48wsx2lhaAUXxHlU4n2NMtLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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