SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6af2fd93bfd21272435bff615db2ff8e01eff77be85f9320a7dfa665bc4850a4' 
  AND token = 'sm3iLp06ISOQhd6AaPVFbYwLhk4yJRfKLNXm6R1ZJN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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