SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a41ec53dee66430d0e166a07459dee5c103c7d92353297662bbb02a3166c415b' 
  AND token = 'kmD5qXn7QH4PzoyABxws29iwBK8mfBhOSP+i+nG5c0I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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