SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7ee634456d676d62f2cc415a55a450a5de04c589cb496804b33a2738c431ad16' 
  AND token = 'X438f+i7JU22zypsqCxE9R97BbuvsCixTvNAH1RwBh4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00067

JSON explain

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