SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36b83678e4d830a239744252efcaff874a8f27bd26ee51fad3e14e1a5ffb1489' 
  AND token = 'QBl05ZQmQdTbUCJpYqS5BsDatRbRBRPsklMr4Wm0lMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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