SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a46878ed4e008ea85bd62cceb9e5dd23642533f247fff65c2290386833a4cd60' 
  AND token = 'gpPvGY1h2ECOzl45EIChnVBLgX0+SH4ZzzT689SBsEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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