SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '551550b74a53cf0f6fe4d0604db660aca69bceac64244e9a254caab63b810746' 
  AND token = '/GVLiyAXSnMYX4H9ImAQJ2ol4UH3/07jLQm9ZqjZums=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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