SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45841273af0e7f3bedafbbbf875b4fccc12becae456b4214253f098e34f5b99b' 
  AND token = 'rBeQkJTClAFGH00iLv+eFGCf2RVcINsk/QuwciI3SO8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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