SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e883e3d426d9b52eba1dbe339cf7d27ebe51779a39360dfc304953bb309d2cef' 
  AND token = '8OC+s0UO/LgHs91AvSVo0lgp5fzcU5q0/L+Utec6iGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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