SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc7470bfcdfd615bb0365d1fe291bde599c35f4fe0f53cacfe27b9f17ab79a4e' 
  AND token = 'ozqXLUn5C9kiBYKhVxkYFNLJfdMXSl3aKHSUJO4efB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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