SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79195160e9ef199a1dd119b7405b8823740cd3dfe59d31cb905014755094e8bf' 
  AND token = 'rUuGX2l4DoIIKUhsgbAZfojf1Rh0F//DeOhBKX8+KmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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