SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '659f3ee0121fbe1fcaa332608926ca88699e872945a62d486174ebdf79bafbd2' 
  AND token = 'UN3W5QqY/alyJMfentmEXzpK2Rih3peV8ndzZPuxnN4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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