SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b4888754c0c9c3787fb4de6b7ecb5a2489c86820daa6eacf04c3f2270b8076d' 
  AND token = 'PnvRng5BZzTPG+nyxgnphKyWv+UdMz21Ou7Wj/4Yz+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}