SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7a84608f00840736ee32fa786bffdb58ee3e95269d3641489b41e7626581aa1' 
  AND token = 'qIE1dAkoV/WaFOvFlljY57uC8SB052+jrEaNPM4LeTY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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