SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16fa2011e8692172f4a79f2a34e384e869bced200601f730e497b1de15a22464' 
  AND token = 'HtmjDVPWnRL8oAcbezW7E9OxRVsK8QKj88/GjiLCZP4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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