SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '938b222185e5a84c6802d16eec7f9158b2f29e9ca95ce1861ea30837989e2eb2' 
  AND token = '1bLHdnQzt2y9EMwwu+d4/7nWL1ROJJpXgUFfxUK7JR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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