SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd21c67f0054ca042301a4b3e25cd123524df01079fe17a73d77968d953d70cef' 
  AND token = '5RjeL1tzewbipX31loFraQfpnVnNSp1Xiq9bKmxokZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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