SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '175338cc7ee638bb6efb12816420c94aa46fb8781b4daed94a625de1f7827498' 
  AND token = 'xZU9BUSplPqW55tOmQt2VgTB1cxtOXnUqw3vOsEMCx0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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