SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d8e1d757f320c9e2e2208e3b7f902429103f97408fdb5e6330716a414d3df67' 
  AND token = '1gxNRo38TXd/rqIM/pMUg9vgGenZhubZKZG+4xtjzpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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