SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '341346e9c06907a726b9e344dbc161054dece9727503b0addf25fae16064f0ad' 
  AND token = '9b/vtyCnMbheS1DhTTpyKoH2BMoTedoR1asWGpQkUKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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