SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9be5d0743e0c2fdf62e6c2adb2c4eaa50cb19a647cddd6c95277ab15daf2478a' 
  AND token = 'iH8ElEOYjjhSMoAo9cTMXHrjm6qoJdHYpE93So+rDVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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