SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '189e6cb62e8a2912dc12da47f362526a21b442fe1df990c0671b251687b23db2' 
  AND token = 'j+AK3P4kVh1UZTRHw/7jt/j+sR6ymeYdflB5BjMFQWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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