SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6046e70c30a7a4177b992b2cd73ae15a14abc304a00302e987ead396efbfcc7b' 
  AND token = 'J1WdrQO2gJUx/EyfUc96mkYpwoT7JjZQfwL2+WWA1KA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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