SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1f6858497efeb03c3e7edb6268f14ac0eda9b862aaac3c817aab6ace3d347d1' 
  AND token = 'L6hI4Ik+V01eQqHdnMsiVA3jMVyCrfwMRYEAYUfMyFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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