SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d8f07205fc936b78f482ce8a20f84e2c2a146a8f7a4e4e64ba5bd9497fb309f' 
  AND token = 'nmRSTaBeqhfQ+dg+sPKrGTa/CoSBojRxVoQjzq1o5ZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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