SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5156a27cedb416eb770304ad82f6f4b7906c4f1de16ce7561dbe5f3a70af6a9' 
  AND token = '4eUWmuFeujCm3BKBGfrljZYmoXHBdEoSfnfGYNktPes=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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