SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c870b94971d84318989bca6bde0ef89bcbfe62eb65e13bcbb66b684885ca7a49' 
  AND token = 'aAsvqA6lcTF5wBXHg4BAsQxXAEpeOCgqI9z9PADPWzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00067

JSON explain

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