SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '952696de3bfd45bfc42268576a07632dcd3adf6355f04527c702c615774dcb13' 
  AND token = 'HeTZ8NfrvIlRrFBzlJ8QfXkzYMV4hHsPbOcFCGH2VuE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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