SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b399142a24628036ea6a0f6852bc99e50422cd092d814132111b2a6e1cb317b' 
  AND token = 'MgXtNrYRTENsVmLR8EBh1hZaMPWo1Xd3a8r/JJ2RCwg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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