SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5149243a62d959068895b6afecaf4bde5f75956825464fa793402205e8e99db7' 
  AND token = 'AJWxbLIN8YA+ckwSCU3zJpaatS68J8PKhYnAOQEN2PY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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