SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbbd81338c915455514560c64d577fadab792186444e90253bdce83524674001' 
  AND token = 'lKQEJyq6a6q2rTTTSex+6/vp08oa4RDZAzEiZIWDp/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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