SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b59650d19abda45832e1d4cf19bcc57264781fb56e586205226bb1c536be48c4' 
  AND token = 'OqDFMYhDzvwG+JP2dP10wKHgr2QjFQv10JLXQM2zbM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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