SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39f359b2a7f883f625ce060304c9ec2faecc68aad8c24ca9a155ca527ee96190' 
  AND token = 'eL1b5qNdMLUtHvTdfIybwoWEam6k246KIzk2WJCK2KY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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