SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3255b0c3a6421d71b017d648cf6049e072a85e32e587174563ff3baf67721b60' 
  AND token = 'GpHzm7DPSPO+UEWBYPepCqO7rrmbZvx6HpkkmVWNPKo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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