SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4aa3e9cd394e188a84c3f5abc763312cb687ff474b2bb967f4fe5472228864c' 
  AND token = 'rgy5z38ClOcnVkIzjf9QeEFtEp1eF3gfalrthRqv1FU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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