SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '121c1114b032ab3b8b0efe53d15124d62f9794ae64f13c7f5d96b5f8588fd43d' 
  AND token = '0Fw/PgjUqrKcINwYbgEfg+nWbisXjAG2HKg0KnS+0U8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00063

JSON explain

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