SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f691df58e52326cf2e1c0b12339a8e1f53e49ec0450967ba1ddf98ff59c888e4' 
  AND token = '7G6W0Fd8rf0wWmDK71tPW8geNhW/SoWftg93vRBoDiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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