SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e5f0f1214f4af8d7e3ecc499b1d36cd853342a6a74849eac8908858790e6d98' 
  AND token = 'X216v/Izo1ZvVooBYLoZ96JcVz8VKji7fY7g4jKLx/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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