SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '077600d35814565f0ec9643c8780967371657b309caed4d73c50fff1f63b33fd' 
  AND token = 'rLtyLQATAzIOLRVmf/mOsgjAZNNcvTxR6JhhNI6/zeU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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